在C＃中的此Boxing示例中会发生什么？

Question

Jon Skeet, has an interesting post titled: " " where he benchmarks the performance of different ways of outputting an integer value.

I am pretty sure the code below boxing, but why Jon is considering it to be boxing? his example is at the end.

int i = 5;
object o = i;
Console.WriteLine("Number is: {0}", o);

The example from Jon's page:

#if CONSOLE_WITH_BOXING
            Console.WriteLine("{0} {1} {2}", i, i, i);            
#elif CONSOLE_NO_BOXING
            object o = i;
            Console.WriteLine("{0} {1} {2}", o, o, o);
#elif CONSOLE_STRINGS
            string s = i.ToString();
            Console.WriteLine("{0} {1} {2}", s, s, s);

PS does not answer my question.

Thank you.

Answer 1

It is boxing, the only difference is on what line it is happening:

not boxing (see http://msdn.microsoft.com/en-us/library/a0bfz20d%28v=vs.110%29.aspx ):

Console.WriteLine("{0} {1} {2}", o, o, o);

boxing:

object o = i;

or consider

three boxing(s):

Console.WriteLine("{0} {1} {2}", i, i, i);

one boxing:

object o = i;
Console.WriteLine("{0} {1} {2}", o, o, o);